Antiphospholipid antibody syndromes are primarily manifested as unexplained thrombotic events. Several antiphospholipid antibodies have been identified, the lupus anticoagulant being the most recognized. Considerable confusion surrounds this "anticoagulant," which is highly correlated with an increased risk of thrombosis. Several assays have been designed for the detection of antiphospholipid antibodies. There are limitations on their efficacy and interpretation requires judgment. Treatment strategies for the clinical manifestations of the antiphospholipid antibody syndrome are being developed. The explosive rise in the volume of literature dedicated to this topic will assure new and improved modalities for evaluation and treatment.